1. Rocks and Minerals Chapter 2 Lesson 1

2. Introduction The famous naturalist John Muir first climbed to the summit of Cathedral Peak in 1869. Located in the Sierra Nevada Range in California, it is 3,308 meters in elevation. Cathedral Peak is mostly composed of granite, a mixture of quartz, feldspar, and other minerals such as hornblende, and mica. Looking down from this tall, narrow peak, you would probably feel like you were on top of the world! Quartz hornblende mica

3. Cathedral Peak in California Elevation of 10,916 feet (3,327 meters)

4. Vocabulary ▪ Mineral-is a naturally occurring solid that can form by inorganic processes and that has a crystal structure and a definite chemical composition ▪ Inorganic-formed from materials that were not a part of living things ▪ Crystal-the repeating pattern of a mineral’s particles that forms a solid ▪ Streak-the color of a mineral’s powder ▪ Luster-term used to describe how light is reflected from a mineral’s surface ▪ Cleavage-how the mineral can split apart ▪ Fracture-how the mineral looks when it breaks

5. Vocabulary ▪ Mohs hardness scale-used to rank the hardness of minerals; it is ranked from 1-10 ▪ Geode-a rounded, hollow rock that is often lined with mineral crystals. Geologists believe crystals are formed inside geodes. ▪ Crystallization-the process by which atoms are arranged to form a material that has a crystal structure ▪ Solution-a mixture in which one substance is dissolved in another ▪ Vein-a narrow channel or slab of a mineral that is different from the surrounding rock

6. What Is a Mineral? ▪ Look at these two substances. On the left is a hard chunk of coal. On the right are beautiful quartz crystals. Both are solid materials that form beneath Earth’s surface. But which is a mineral?

7. Defining Minerals A mineral is a naturally occurring solid that can form by inorganic processes and has a crystal structure and a definite chemical composition. For a substance to be a mineral it must have all five characteristics. So, is either quartz or coal a mineral?

8. Properties of Minerals ▪ Naturally Occurring All minerals are substances that are formed by natural processes. Quartz forms naturally as molten material called magma cools and hardens beneath Earth’s surface. Coal forms naturally from the remains of plants that are squeezed tightly together. ▪ Solid A mineral is always a solid, with a definite volume and shape. The particles that make up a solid are packed together very tightly, so they cannot move like particles that make up a liquid. Coal and quartz are solids.

9. Properties of Minerals ▪ Crystal Structure The particles of a mineral line up in a pattern that repeats over and over again. The repeating pattern of a mineral’s particles forms crystals. A crystal has flat sides, called faces, that meet at sharp edges and corners. The quartz has a crystal structure. In contrast, most coal lacks a crystal structure. ▪ Form by Inorganic Processes All minerals must be able to form by inorganic processes. Quartz can form naturally as magma cools. Coal comes only from living things- the remains of plants that lived millions of years ago. But some minerals that can form from inorganic processes may also be produced by living things.

10. Properties of Minerals ▪ Definite Chemical Composition A mineral has a definite chemical composition. This means that a mineral always contains certain elements in definite proportions. An element is a substance composed of a single kind of atom. Quartz always contains one atom of silicon for every two atoms of oxygen. The elements in coal vary over a wide range.

11. Classify Complete the checklist. Are quartz and coal minerals or only naturally occurring substances? Mineral CharacteristicsQuartzCoal Naturally occurring Can form by inorganic processes Solid Crystal structure Definite chemical composition

12. Apply Classify wood by writing a check mark to the characteristic it has. Then answer the question: Is it a mineral? Explain your answer. Mineral CharacteristicsWood Naturally occurring Can form by inorganic process Solid Crystal Structure Definite chemical composition

13. Difference between Rocks and Minerals

14. Let’s Watch

15. Let’s Apply! In your Science notebook, create a Venn diagram like this one to compare rocks and minerals. RocksMinerals